STUART JORDAN recalls the history of the first Tay Railway Bridge.
In 1854 there was a train ferry across the River Tay, carrying the railway across the firth. Plans were drawn up to replace this ferry with a permanent bridge, but Royal Assent was only given to the Act of Parliament in 1870, with the foundation stone laid the year after.
The engineer in charge was Thomas Bouch. He decided on a design that combined both wrought iron and cast iron in a lattice. This style of construction had previously been used on the Crystal Palace, as well as in viaducts in France built by Gustave Eiffel (of the Paris tower fame).
The Tay Bridge after construction, showing the girder lattice making up the spans
Once construction was begun, it was realised that the bedrock that the piers were to rest on was much lower than the original survey found. To remedy this, the bridge was redesigned. Bouch reduced the number of piers and increased the span of the girders. The piers now sat on iron caissons surrounded by brick. The original brick piers were replaced with iron girders, designed to hold the weight of the lengthened spans more effectively.
The bridge, crossing the Firth of Tay from Dundee to Fife, was only a single track. It was inspected by the Board of Trade in February 1878. A speed limit of 25mph was suggested, due to the stiffness of the structure. The bridge opened on 1st June 1878 for passenger traffic. Queen Victoria herself crossed the Tay Bridge on her way back to London from Balmoral. Shortly after, in 1879, the Queen knighted Thomas Bouch.
The Tay Bridge after the collapse of the central spans
Just six months after his knighthood, Thomas Bouch faced the ruin of his reputation. On the night of 28th December 1879, high winds caused the central spans to give way and the bridge collapsed. The train crossing the bridge at the time was carrying 75 passengers and crew – all perished as it plunged into the river.
North British Railway locomotive 224, after being recovered from the river. The locomotive was restored and went back into service
The enquiry afterwards found that the bridge design could not withstand high winds. The wind speed on that faithful night was gale force 10 or 11 (55-72mph). The fact that it was passed by the Board of Trade made the incident particularly notorious in the world of engineering. Bouch’s reputation was destroyed and he died soon after the enquiry closed.
Plans were made almost immediately to build a second Tay Bridge – and we will look at that in the second part of this article.